Background

State of Oregon
National Resources Inventory (NRI)

The NRI in Oregon captures data at more than 17,000 scientifically selected sampling sites. It is designed to provide information on the status, condition, and trends of land, soil, water, and related resources on the nation’s non-federal land. Data collection on federal lands is limited to ownership and area in large water bodies.

Information collected on non-federal lands includes land cover and use, soil types, soil erosion, prime farmland soils, wetlands, habitat diversity, selected conservation practices, and related resource attributes. This data is then statistically expanded to provide estimates of resource conditions on all non-Federal lands in Oregon. NRI estimates are available for the years 1982, 1987, 1992, and 1997.

The information is statistically reliable for national, statewide, and multi-county use. Generally, however, interpretations at the local level must be made with caution.

Statistics derived from the NRI database are estimates and not absolutes. This means that there is some amount of uncertainty in any result obtained using NRI data. Each NRI estimate has a different level of precision and the standard error for each estimate may be found in the NRI data tables.

The margin of error is 1.96 times the estimated standard error, and can be used to construct a 95 percent confidence interval for the estimate. The lower bound of the interval is obtained by subtracting the margin of error from the estimate; the upper bound is obtained by adding the margin of error to the estimate.

Data collected for the 1997 NRI update were collected using photo interpretation, field office records, historical records and data, a variety of ancillary materials, and a limited number of onsite visits.

ESTIMATES FROM THE 1997 NRI DATABASE (REVISED DECEMBER 2000) REPLACE ALL PREVIOUS REPORTS AND ESTIMATES.  Comparisons made using data published for the 1982, 1987, or  1992 NRI may produce erroneous results. This is due to changes in statistical estimation  protocols, and because all data collected prior to 1997 were simultaneously reviewed  (edited) as 1997 NRI data were collected.   All definitions are available in the glossary.  In addition, this December 2000 revision of the 1997 NRI data updates information released in December 1999 and corrects a computer error discovered in March 2000.

For More National NRI Background information click here.

Send comments and suggestions to the Oregon Resources Inventory Team
Last Modification: Monday, July 28, 2003

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